Some of the hardest parts of a house to seal are the windows, which are really just big holes in a wall filled with glass, wood, and plastic. The reason it's so difficult to seal around windows is that the hole spans many layers of different materials—drywall, framing, exterior sheathing, house-wrap, and siding. In a superinsulated house, there are even more—the house featured in this video has an extra two layers of rigid foam on the outside...

Read the full article at: http://www.greenbuildingadvisor.com/s...

Read more about the importance of air-sealing for energy efficiency and durability: http://www.greenbuildingadvisor.com/a...